1. Field of the Invention
The invention relates to slickened or siliconized flame resistant fiber blends that are well suited for use in mattresses, boxsprings, upholstered furniture, fiber-filled bed clothing, office panel fabric, transportation seating or any end use application where a soft materials are desired for flame resistant (FR) purposes. Some forms of this invention include:                1) FR thermally bonded or resin bonded highloft comprising fiber blends of FR fibers with non-FR fibers, some fibers of which are slickened.        2) FR needlepunched nonwovens comprising fiber blends of FR fibers with non-FR fibers, some fibers of which are slickened.        3) FR loose fill fiber comprising fiber blends of FR fibers with non-FR fibers, some of which are slickened; and        4) FR woven and FR knit fabrics produced from yarns comprising fiber blends of FR fibers with non-FR fibers, some fibers of which are slickened.        
The FR fibers incorporated into these blends include both char forming FR fibers and/or slickened and oxygen depleting FR fibers. Either or both or these types of fibers may be slickened or siliconized. FR char-forming fibers are those which exhibit little shrinkage when exposed to direct flame and are not spun from polymers manufactured with halogenated monomers. Oxygen depleting FR fibers are spun from polymers manufactured with halogenated monomers. Oxygen depleting FR fibers generate decomposition gases, when exposed to flame, which help to prevent autoignition of the decomposition products coming from underlying layers of, for example, polyurethane foam and they also help extinguish residual flame which may emanate from overlying dress cover fabric or the like. Oxygen depleting gases from the fibers spun from polymers manufactured with halogenated monomers, when included in the fiber blend, also coat and protect the carbonaceous char formed during decomposition of the char forming FR fibers. This invention also discloses, surprisingly, that a significant percentage of slickened or siliconized non-FR fibers such as natural, synthetic, or even cellulosic fiber, such as lyocell or rayon, can be added to the fiber blend and still perform well in open flame resistant applications. These synergistic slickened or siliconized fiber blends, which impart soft and comfortable end use properties, are able to withstand extended periods of direct flame exposure with minimal shrinkage. The use of slickened or siliconized flame resistant fiber blends as recognized in this invention, also result in softer and more comfortable open flame resistant composite articles with improved water resistance, while also permitting the continued use therewith of conventional non-FR dress cover fabrics and conventional non-FR polyurethane foams and the like.
The advantages of slickened or siliconized flame resistant fiber blends include:                a) imparting a softer, silkier, slicker, more luxurious hand (feel) to a FR product;        b) better water resistance properties than FR fiber blends that do not contain the slickened/siliconized FR fibers; and        c) when included in mattress and upholstered furniture the slickened/siliconized FR fiber blend makes the final composite article quieter, when compressed and stretched, than a comparable composite article which does not contain the slickened/siliconized FR fibers.        
2. Description of the Related Art
It is well known in the textile industry to produce FR products for use in upholstered furniture, mattresses, boxsprings, automotive seating, public transportation seating, aircraft seating and the like, using needlepunched, highloft, spunbond or spunlace nonwoven fabrics or woven or knit fabrics formed of natural or synthetic fibers which are either inherently FR or treated or coated with fire retarding chemicals. Conventional fire retarding chemicals include borate-based, halogen-based, phosphorus-based, melamine-based and/or antimony-based chemicals. Unfortunately, these FR products have not previously imparted the comfort and/or softness features desired by manufacturers of end-use articles which must be made open flame resistant.
Some of the flame barrier fabrics currently being used with the goal to pass open flame resistant tests, such as TB129, TB133, TB603 and TB604; but which do not have the comfort features described in this invention include:                1) Woven polymer coated 100% fiberglass flame barrier (Sandel® Fabric, Sandel International Inc.);        2) Woven or knit core-spun yarn based flame barrier, where natural and/or synthetic fibers are wrapped around a multifilament fiberglass core and then optionally treated with FR chemicals and/or a coating of thermoplastic polyvinyl halide composition, such as polyvinyl chloride (Firegard® Seating Barriers, Intek; Firegard® Brand Products, Chiquola Fabrics, LLC);        3) Nonwoven hydroentangled spunlace flame barrier made of 100% p-aramid or p-aramid fiber blends with other fibers (Thermablock™ Kevlar® Z-11, DuPont Company);        4) Woven or knit core-spun yarn based flame barrier where natural and/or synthetic fibers are wrapped around a multifilament glass or a spun p-aramid core yarn and then optionally treated with fire retarding chemicals and/or a coating of thermoplastic polyvinyl halide composition, such as polyvinyl chloride (Firegard® Seating Barriers, Intek; Firegard® Brand Products, Chiquola Fabrics, LLC, Alessandra FR barrier cloth, McKinnon-Land, LLC); and        5) Nonslickened highloft and needlepunched FR barriers made from blends of either inherently FR or fire retarding chemically treated fiber blends (Protech™, Carpenter Co; Esyntial Safe™, Western Nonwoven Inc.; VitaSafe™, Vita Nonwovens, fire retarding chemical treated cotton battings, Jones Fiber Co.).        
It is well known in the industry to manufacture slickened and/or siliconized polyester fiber blends (U.S. Pat. Nos. 4,304,817 & 4,281,042) for improved softness, comfort and silky feel; unfortunately, these products usually have much worse flame resistance properties than their non-slickened counterparts. Slickened polyester has also been blended with some minor amounts (up to 20%) non-slickened flame retardant fibers (U.S. Pat. No. 4,199,642). This blend will not pass the aforementioned tests for a flame barrier. It is the object of the present invention to describe flame resistant fiber blends that provide the desired softness, comfort and feel, while still providing the required level of flame protection.